The opioid epidemic in the United States necessitates the development of novel interventions that are critical to preventing opioid fatalities. To help combat this crisis, our goal is to develop a respiratory sensing device to transmit an early alert of an impending respiratory failure to the victim and to designated family members, friends, and/or the Police Emergency Unit enabling life-saving intervention. To have an impact on saving lives, the sensing device must be convenient and comfortable so that the user will wear it all times. It must also to be accurate and robust - false alarms will discourage long-term use, and, conversely, missed diagnoses has serious consequences The device described in this proposal will apply an innovative near-field coherent sensing (NCS) method to measure the cardiopulmonary system without direct skin contact, enabling comfortable long-term wearing. It will have a dual-mode operation that allows for high user mobility indoors and outdoors in the active mode, and reliable in-home protection in the passive mode which allows usage even if the user has forgotten to recharge the battery. The research proposal aims to optimize the device hardware and software, in terms of identification of changes in respiration that signal impending respiratory arrest. This low-cost innovative technology will also provide robust diagnostic accuracy for early detection and prevention of fatal opioid overdoses. The proposal is composed of three specific aims: 1) Development of a wearable device with a sensing tag for respiratory monitoring with network connectivity; 2) Benchmarking early respiratory signatures of the proposed tag by airflow pressure transducers and respiratory inductance plethysmography (RIP) during polysomnography; 3) Construction of engineering phantom models for variation analysis and design guidance. The Cornell Electrical and Computer Engineering and the Weill Cornell Medical College research team will use their expertise in their respective tasks, and will work together on comparative testing, data analyses and revisions based on feedback information. The engineering team will validate the tag designs on a phantom model and on a limited number of users. The main goal is to establish the design procedures and parametrical analysis for eventual use in the community to combat the opioid crisis. At the Sleep Center at Weill Cornell, gold- standard techniques will be employed to monitor respiration with calibrated polysomnography to benchmark the proposed sensor. The main goal is to establish physiological evidence for early respiratory symptoms of impending opioid overdose in preparation for eventual full-scale clinical studies. The successful development of the proposed device will allow for accurate monitoring of symptoms of respiratory depression to enable early intervention to prevent opioid overdose.